


Swear By the Moon

by SherlockiansGetBored



Category: Sherlock (TV)
Genre: Alternate Universe - Werewolf, Friendship, Original Character(s), Supernatural Elements, Werewolf Sherlock, What-If
Language: English
Status: In-Progress
Published: 2016-11-02
Updated: 2016-12-22
Packaged: 2018-08-28 17:57:15
Rating: Teen And Up Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 12
Words: 4,492
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/8456251
Author URL: https://archiveofourown.org/users/SherlockiansGetBored/pseuds/SherlockiansGetBored
Summary: Sherlock and John's friendship becomes stronger through the struggles of dealing with Sherlock's secret identity. Sherlock is a werewolf.





	1. Chapter 1

"Sherlock, there's a client at the door," said Mrs. Hudson. She set a tea tray on the side table next to John's chair.

"Thank you," John said, taking a cup for himself.

"I would say to send him away. He clearly doesn't think the case is worth my time himself, but I have nothing better to do so you might as well send him up anyway," Sherlock said. "And bring some food up while you’re at it. I haven't eaten in five days."

"I'm not your housekeeper!" Mrs. Hudson called as she left to answer the door.

"Five days, Sherlock? How have you not starved to death?" John asked.

"As a doctor, you know it is possible to survive longer than five days without eating," said Sherlock.

"Five days is still a long time, even for you," John said.

The client, in about his late twenties, sat in the regular wooden client’s chair between Sherlock and John.

"Why are you here?" Sherlock asked.

The boy looked nervously at them both, hesitant to speak. "Well...you see I..."

"Yes?" asked Sherlock, impatiently.

"Two nights ago, I was taking a walk in the woods not far from my house, and I know this sounds crazy, but I...I saw a werewolf."

"A werewolf?" John asked, skeptically.

"I've gone to the police, but of course they just think I'm mad."

"Describe it to me. Everything you remember from that night," Sherlock said. As he said this, he brought his hands together, resting his fingertips under his chin and closing his eyes.

"I only moved here recently. I was taking a nighttime stroll at around 7:30 to get a feel for the land. By the time the sun had set, I heard a wolf's howl in the distance. I didn't think much of it. I had planned to turn back soon, but as I went on I saw a man in the distance. I could only make out a silhouette. I saw him change right before my eyes. He took on the shape of a wolf. I took off running before I could get a good look at him."

"Are you sure it wasn't just someone out with their dog?" John asked. "It was dark."

"I'm positive. I know what I saw."

"So what?" Sherlock said with his eyes still closed.

"Sorry?" the boy asked.

Sherlock opened his eyes and leaned forward towards the boy. "You saw a werewolf. Why does it matter? What proof do you have? _Why are you here_?"


	2. Chapter 2

"I went out the next morning to see if there was any sign of what I had witnessed. I found deep, large scratches in a tree, only meters from my house." He pulled out his mobile to show a picture of the markings. "I could be in danger. The police refuse to help me, so I was hoping you would. I want you to help me kill it."

Sherlock smiled. Finally something fun to occupy his mind. 

"Done," he said, holding out his hand to the boy. "We'll meet in two hours."

"What was your name?" John asked, showing him to the door.

"Alan Talbot," he said. "Afternoon."  
\--------------------------------------------------------------------------------------------------------------------

"Are we seriously doing this, Sherlock?" asked John as he and Sherlock walked up to Alan's door.

"Why not? Would you rather I try another 7% solution? Which should it be today: morphine or cocaine?"

"No! You are not starting that again."

Before they had reached the front porch of the small English cottage, the front door swung open. Alan stared for a moment when he saw Sherlock carrying a giant harpoon.  
When he had found his voice, Alan said, "No need to waste time. Should we go?"

"I doubt you would find anything with this daylight, but it would be easier to make out those scratch marks before it gets dark. Show them to me," said Sherlock.

"Oh, all right. Follow me," Alan said.

They followed him around the house to the tree with the claw marks. Sherlock deduced from the random pattern that the marks were authentic, and although they were high up on the trunk, they could be from a large dog.

"I don't have a dog," Alan had responded.

"Of course you don't," John muttered under his breath.

Seeing that it might be a while until the creature’s appearance, Alan invited Sherlock and John inside for a small dinner.

Once they set out again, they had only hiked a few paces into the forest when it started to get dark.

"We'll have to wait here," said Sherlock. He sat up against a tree, and the other two did the same.  
\--------------------------------------------------------------------------------------------------------------------

"What time is it?" asked John, impatiently.

"7:45," Sherlock said, glancing at his watch. "The same time you saw the wolf."

"We've been here for nearly 4 hours," John said.

They continued to wait nearly another hour when John whispered to Sherlock, "How long are we going to wait for nothing?"

"As long as it takes," he responded. John was beginning to wonder if Sherlock had only come to prove this man wrong and possibly insane.

Then it happened. A loud howl echoed from a mile away.


	3. Chapter 3

"What do we do, now?" John asked.

Alan looked terrified. He had really been hoping he had been wrong about all of this.

With every passing minute, the sound moved closer towards them until a deep, low growl could be heard. The creature was just out of eyesight.

The leaves rustled. John's grip tightened on his revolver.

"Wait here," Sherlock said as he stood up armed with his harpoon.

John hoped that Sherlock actually knew what he was doing. John stayed behind with Alan who wouldn’t come any closer to the possible werewolf.

Sherlock was far ahead now, only a short length from the creature. He saw it cowering behind a large bush, but it spotted him too.

With the first lunge, Sherlock was able to keep it back, piercing it in the chest with the tip of his harpoon, but the second lunge had stronger force, snapping the harpoon in half.  
Sherlock threw it to the side. Luckily, he knew how to fight. He threw a punch at the giant wolf's jaw.

The wolf's claw tore at Sherlock’s leg, and its teeth sunk into his shoulder. Sherlock kicked it away just as John came running towards them. John fired at the wolf, hitting it in the shoulder. It whimpered and ran off deep into the dark.

Sherlock collapsed to the ground, groaning in pain. He held his injured leg tightly.

"Let me see," said John, rushing towards him.

"No, stay back," said Sherlock, with his teeth clenched.

"I'm a doctor. Let me help."

"I know you're a bloody doctor! I'm fine!"

"Alright! At least let me get you back to the house." Sherlock gave in and used John as a crutch. Alan had caught up with them once he was sure the wolf had gone.

Sherlock sat by a fire inside while John called for a cab on his mobile. Hopefully, one would be willing to come this far out of the city this late at night.

John didn't bother calling for an ambulance, but Sherlock eventually let him put some gauze on his leg. He didn't tell John about the bite marks on his shoulder.


	4. Chapter 4

Sherlock said it was just a regular wolf that he had seen that night so there was no reason to try contacting the police a second time. None of the cases they had for the next couple weeks were close to as exciting as this one, even if it barely counted as a mystery.

Even with things back to normal, John started to notice Sherlock was different. He had always kept mostly to himself, but he started locking his door at night. He would go up early, and come out late in the day. He was eating more, but he seemed paler than normal.

One morning, he came out looking worse than ever. He clearly hadn't slept at all the night before.

"Are you alright?" John asked him.

"Yes, I'm perfectly alright. Why wouldn't I be?"

"No reason," John said. He went back to reading the newspaper.

John glanced up to see what book Sherlock had just picked up. It had a thick binding and was titled...

"Signs You May Be a Werewolf?" John read out loud. "Why the hell are you reading that?"

"It's educational. If we were ever to encounter a real werewolf, we would need to be prepared. Anyone could be a werewolf, John."

"No, they couldn't. Werewolves don't exist!"

"How would you know?"

"They can't. They're made up."

"Just because you haven't seen one doesn't mean they don't exist."

"Do you actually believe that rubbish?" John asked. He was expecting Sherlock to answer reasonably, "No, of course not," but he instead got the complete opposite.

"Yes."


	5. Chapter 5

Now, John was even more worried about Sherlock. His odd behavior was only worsening. John started to think back to that case with the wolf encounter more often. He decided to take a walk that night to sort through everything that was going on.

"I'm going out," he said. 

"Where?" asked Sherlock.

"Just a walk. I need some air," John said. He took his jacket and left Sherlock plucking the strings of his violin by the fire.

On his walk, he tried to think of a way to help Sherlock. It would be a lot easier if he actually knew what the problem was.

When he got back, Sherlock was, unsurprisingly, in his room. Out of curiosity, John listened by the door. At first he heard nothing. Good, he's finally getting some sleep, he thought. 

He started to walk towards his own room when he heard a scratching noise from behind the door against the wood floor. It was soft. He only heard it once. For now, he ignored it and went to bed.

A few nights later, John was taking another walk, and when he got to the corner of Baker Street, he looked up to see that tonight was a full moon. He wished Sherlock would come out to enjoy things like this with him.

He was startled to hear a wolf's howl. There were no wolves near Baker Street. And even more worrying, the noise was coming from inside his flat.

John ran back to the flat with his gun in hand. He ran up the stairs and kicked open Sherlock's locked bedroom door. Standing in front of him with its teeth bared was a huge, black wolf. Sherlock was nowhere to be seen.


	6. Chapter 6

John slammed the door shut with his back to it breathing heavily.  Had he really just seen...a wolf?

All the pieces started to come together.  Now everything made sense.  John kept his gun by his bed that night, but he prayed that he wouldn't need to use it.

\--------------------------------------------------------------------------------------------------------------------

The next morning Sherlock and John sat in the living room as normal drinking Mrs. Hudson's tea.

"Sherlock, remember that night with the wolf?"

"Yes," Sherlock said, trying to hide the panic in his voice. Had John finally discovered his secret?

"Did your leg ever heal from it?" John asked.

"Yes," Sherlock said.

"Show me."

Sherlock sighed and pulled him the leg of his trousers to show that there wasn't even a scar left.

"Sherlock, how did it happen?"

"How did what happen?"

"Sherlock, I know...I know you're a...werewolf."

Sherlock looked at John, terrified that he had discovered his secret, terrified of what John would think of him now.

Sherlock unbuttoned his shirt to show John how it had really happened.  The marks on his right shoulder had turned black.  They would never heal.

"Why didn't you tell me?" John said angrily.

"I couldn't," said Sherlock.  He couldn't look John in the eye.

"Why didn't you trust me?" John said in a hurt whisper.

All Sherlock could say was, "I'm sorry."


	7. Chapter 7

After moments of silence had passed, Sherlock got up and locked himself in his room.  Or at least he kept the door shut.  The lock was still broken from when John had forced the door open the previous night.

John left him in peace, knowing he wanted to be alone, but when he didn't come out for an hour (which John spent on his laptop reading the comments on his blog), John got up from his chair to check on him.

"Sherlock?"  He knocked on the door lightly.  "Sherlock."

Sherlock opened the door.  "What is it?  I'm busy."

"Doing what?"

"An experiment," Sherlock lied.

"I want to help," John said.

"I don't need help.  The procedure is fairly simple."

John took a second to realize he was talking about the "experiment".  "I meant I want to help _you_.  You know...your wolf problem?"

"Oh," said Sherlock.

They agreed that tonight John would see how approachable Sherlock was in wolf form.  After last night, John had a pretty good idea, but he wanted to be sure.  There could still be a way to tame him.

\--------------------------------------------------------------------------------------------------------------------

John made sure Mrs. Hudson fixed the lock on Sherlock's bedroom for obvious reasons.  She didn't question why it was broken in the first place.  Sherlock was always breaking things. First it was the doorbell, then the microwave, he had shot the wall multiple times, and now she could add the lock on his door to the list.

John prepared his gun for the long night ahead.  If he needed to use it, he'd aim for Sherlock's foot.  Well...his paw.  After all John and Sherlock had been through, this was definitely the strangest, and possibly the most dangerous thing they had ever done together, and it was themselves who would be putting each other in danger.

John stood outside Sherlock's door, listening for any sign of transformation.  There was a loud groan that turned into a whine.  John waited a little longer before slowly entering the room.

Sherlock was crouched behind his bed low to the floor.  His black coat was thick and sleek.  He was the size of a bear, and his yellow eyes glowed.

John swallowed his fear.  He needed to do this.  For Sherlock.  "Sherlock?”

The wolf raised his head to listen. John cautiously stepped towards him. He was only inches away when the wolf started to growl softly. Another step and the growl grew louder.

“Shh. Quiet,” John said. “Can you understand me?”

The wolf stopped to tilt his head in confusion. One more step set him off. The wolf lunged at John. John didn’t try to calm him down again. He ran for his life.


	8. Chapter 8

**Notes for the Chapter:**

> Thank you so much to everyone who has taken the time to read this story. There are still many more chapters to come, but I really appreciate all of the support that I have received so far. If you have any comments or suggestions, let me know.

“What happened?” Sherlock asked John the next morning. Sherlock had been able to work out that he was a werewolf long before John did, but he could never actually remember his own transformations.

“You were fine at first, but when I got too close you attacked,” John said.

Sherlock looked at him apologetically. He had described himself as a sociopath on many occasions, but that description was not entirely accurate. It didn’t mean he couldn’t care. He didn’t want to hurt his best friend.

“What was it like?” John asked. “Tell me everything from the beginning.”

Sherlock started by explaining everything that had happened the night at Alan’s house up until John rescued him. “I honestly believed it was just an ordinary wolf, even after observing its unusually large size. My transformations started out small. I didn’t start changing into full wolf form until recently. Early on, I did start to notice the common signs: longer nails, faster hair growth, unusual sleeping patterns.”

“You already had that one, mate,” John interrupted.

Sherlock continued, “It can be difficult to separate fact from fiction. For example, a fear of water is false. Also, it is true that a full moon worsens the symptoms, but I can change any night. Other signs include improved agility, meat cravings, a short temper. Once the full transformations started, I would wake up in the morning not remembering anything from the night before. It became obvious to me when my shoulder wound wasn’t healing and I was waking up on my bedroom floor with scratches on the furniture.”

John didn’t know what to say. He felt horrible that his best friend had been forced to go through this alone. He would do anything for Sherlock. Sherlock wouldn’t have to be alone anymore. John would make sure of that.

\--------------------------------------------------------------------------------------------------------------------

“Sherlock, I just had a thought,” John said. “If that bite turned you into a werewolf that means that Alan was right. There is a werewolf running loose somewhere. People could be in danger.”

“I’ll phone Lestrade. It’s unlikely the police will believe the situation, but he is most likely to be willing to help,” Sherlock said. He was worried about going outside at night. He could be unpredictably dangerous without the security of being locked up, but John was right. They needed to find that werewolf before it did too much damage.

\--------------------------------------------------------------------------------------------------------------------

“Are you sure there was a wolf? Here in London?” Lestrade asked over the phone.

“No, not in London. Just outside of it. We were nearly killed when it attacked us the other night,” Sherlock said.

“I don’t know. Wolves…not my division.”

“We need your help.”

“Why didn’t you call the night it happened?”

“We were a bit preoccupied that night. We were expecting worse.”

“Alright, I’ll be over there as soon as I can. Text me the address.”


	9. Chapter 9

Lestrade pulled up in his police car soon after Sherlock and John. Because John’s gun was technically illegal, he brought a metal pipe tucked in the waistline of his jeans to use in front Lestrade if it was necessary. Hopefully, Lestrade had improved at making a kill shot since their encounter with the hound in Dartmoor.

“What exactly are we looking for?” asked Lestrade.

“A grey wolf, slightly smaller than a grizzly bear,” said Sherlock.

“We should wait until it gets a little darker,” said John.

“Why?” asked Lestrade.

“Um…” John tried to think of an excuse quickly.

“Because this kind of wolf is more likely to come out at night,” answered Sherlock. “Obviously.”

“Yeah,” John agreed.

“There is something I need to do first that could pass the time, though,” said Sherlock.

“What?” asked Lestrade.

“Well, we can’t investigate the scene of a crime without our client.”

\--------------------------------------------------------------------------------------------------------------------

Sherlock knocked loudly on Alan Talbot’s front door. Alan was surprised that anyone would be coming to his door at this time.

“Is there something wrong?” he asked, once he recognized who was at the door.

“No. There’s nothing wrong,” Sherlock assured him. “We just need your help finding that wolf again.”

“Why do you need my help?” asked Alan. He was clearly still terrified of the beast.

“We need you to go into the forest and see if it attacks you,” said Sherlock.

“What!?!” exclaimed Alan, followed by a similar reaction from both John and Lestrade.

“Oh, relax. We won’t let anything actually attack you, but it will be easier to catch it if we have another person to use as a distraction while Lestrade tries to shoot it.”


	10. Chapter 10

Somehow, Sherlock managed to convince Alan that he would be perfectly safe going into the forest as bait. They didn’t have to wait long to begin the search. Once it became dark, the full moon helped to give them some light along with some torches they had brought.

This time, they all went a bit deeper into the forest than they had during their first encounter. They wanted to be sure that the wolf would appear. The time spent sitting in the eerie silence ticked by for another hour.

A phone rang. John jumped with surprise. Sherlock just looked annoyed, but he also noticed the caller ID said Paul K. Alan answered his phone.

“Hello?” he said. “…Yeah, I know…Really? Wow, sorry about that, man…yeah, sure. That’s fine…” He looked up, realizing everyone was staring at him and waiting for him to hang up. “Hey, Paul. Sorry to interrupt, but I’m kind of in the middle of something important so I’m going to have to call you back…yeah, thanks. Bye.”

He hung up, looking slightly embarrassed. “Sorry about that,” he said. “Hey, while we’re waiting does anyone want some sugar cookies?”

“You brought cookies?” asked Lestrade.

“Yeah, I just thought we might be here a while so I brought some food for while we’re waiting,” he said.

They each took one except for Sherlock who mumbled something about not eating during work. The cookies were all gone in minutes. Only seconds later, the wolf was upon them. It jumped out of the shadows and snarled ferociously at them. Everyone stood and backed away slowly, but Alan was the closest. The wolf attacked, taking a chunk of flesh from Alan’s right arm.

Lestrade cocked his gun, but he couldn’t hold his hands steady. Shooting a wolf twice its average size was not in his training.

“Give me that,” said John, yanking the gun from his hands. With two shots to the heart, the wolf lay limp on the ground. It was dead.

John handed the gun back to Lestrade and rushed over to Alan. “Let me see it. I’m a doctor.” Alan moved his blood soaked hand away from the wound. It was deep. “Sherlock, your scarf. Now.”

Sherlock handed his scarf to John without a word. John wrapped it around Alan’s arm tightly and tied it in place. “Lestrade, call an ambulance,” he ordered. “Sherlock, come here. We have to move him to shelter.” He decided it wasn’t a good time to tell Alan that he would now live the same fate as Sherlock. Alan was now a werewolf.

They had only walked a few meters when Alan fainted from shock. He needed to be treated, but he needed to be taken somewhere warm. John and Sherlock dragged him with Lestrade on the phone, walking behind them.


	11. Chapter 11

John collapsed under Alan’s weight.  Sherlock’s grip had loosened which left John dragging most of the weight himself.

“Sherlock, can you help a bit more?” John asked, annoyed.  After a few more steps, he looked to see why Sherlock had stopped helping.  “Sherlock?”

Sherlock let go of Alan’s arm completely and backed away from both of them.

“Sherlock, what is going on?  Help me,” said John, angrily.

Sherlock didn’t say a word.  He looked down at his hands.  His eyes were filled with fear as he began to change form.  His nails grew longer and sharper.  His eyes glowed bright yellow.  It wasn’t long before he was in full wolf form.

Lestrade stared at the giant, black wolf in front of him.  He was frozen with shock.  John quickly rested Alan against a nearby tree.  He pulled out the metal pipe that he had brought with him and started to walk towards Lestrade, ignoring the wolf.

“Greg, I’m sorry I have to do this,” he said.  Before Lestrade could ask what he meant, John struck him on the head with the pipe.  He was knocked out instantly.

“Sherlock?” John said, turning to the wolf.  “Sherlock, listen to me.  It’s me. John.  Remember?”

The wolf started to creep towards him slowly.  John stood his ground.  “Please be able to understand me,” he whispered, more to himself than to Sherlock.

“Sherlock, sit,” John said louder.  At first, the wolf seemed unphased, but then he paused.  There was a flicker of recognition.

Alan groaned from where he was resting.  The wolf’s head snapped around to face his new opponent.  He snarled at Alan, and just as he was about to lunge, John ran up behind him and hit the wolf over the head with the pipe.  The wolf crashed to the ground, unconscious.


	12. Chapter 12

John found some handcuffs on Lestrade which he used on Sherlock’s front paws while he was still unconscious.  He also grabbed Lestrade’s gun in case he needed to use more than a metal pipe.  He realized that the ambulance for Alan would arrive soon.  He couldn’t risk anyone discovering the situation he was in so he was forced to carry Alan all the way back to his front porch.  The ambulance was already pulling up when they reached their destination.

John hid the gun behind his back as he went into a detailed diagnosis of Alan’s injuries.  He explained that he was a retired army doctor when the medics looked surprised at his expert analysis.  Luckily, they did not ask for too much detail of how the events leading up to the injury had taken place.  They only needed to know that it was a wolf bite and that it had happened about half an hour ago.

As soon as the ambulance drove off, John returned to Sherlock and Lestrade.  Lestrade had just woken up and was desperately looking for his gun without taking his eyes off of the wolf that had figured out how to stand, but was still restrained from walking by the handcuffs.

John pointed his gun at Lestrade.  “Don’t move!” he ordered.

Lestrade moved his hands instinctively above his head.  “What is going on?”

“Don’t ask questions.  Just stay where you are,” John said, calmly.

John walked towards Lestrade and hoped that he wouldn’t make things more difficult than they needed to be.  Luckily, his military training paid off.  He was able to approach Lestrade fast enough to knock him out one more time.  He had to act quickly and made the difficult decision of leaving Sherlock behind while he drove Lestrade home in his police car.

“Where am I?” Lestrade asked when he woke up.  It was 11:30 P.M.

“We were at a bar where you had too much to drink,” John lied.

“No, wait,” Lestrade interrupted.  Everything started to come back to him.  “We were in a forest with Sherlock.  We were hunting a wolf.  That guy, Alan…he got bitten.”

“I think you should probably get some sleep,” John said.  “Sherlock has been at our flat all night.”

“No, I’m sure this was real.  We were heading out of the forest when Sherlock…” he couldn’t continue.  He couldn’t believe what he had seen.  “Sherlock turned into a wolf.”

John tried to look confused about this.  “What?”

"You were there," said Lestrade.

“I was at the bar where you made a complete fool of yourself.  I should have taken a video.”

“But it seemed so real.”

"Real?  Sherlock turning into a werewolf?  It was just a dream," said John.  “You’ve been out for a while.

"You're right," said Lestrade, realizing how crazy he sounded.

John nearly sighed in relief.  "I have to get home now," he said.  He left before Lestrade could change his mind.

John got a cab back to his flat.  He decided that he could go back to the forest for Sherlock in the morning.  He didn't want to deal with Sherlock as a wolf.  He hoped that Sherlock would be able to survive one night in the forest.

**Notes for the Chapter:**

> I'm taking a hiatus with this story until after the first episode of Series 4 (ten days away!) so that I can start posting a seven chapter story as a countdown until the new series. Hopefully I will have more chapters written for this story by then so that I can start posting more regularly.


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